What about a Russian Dominion of Alaska, in a TL in which Russia liberalizes a century earlier?
Mid-18th century Russian liberalization is quite extremely unlikely without massive butterfly activity. Even if this liberalization did occur, a mid-19th century Russian Dominion of Alaska (whatever you mean by that term) is still not likely to come to pass. Nor, to tie this into the opening thrust of this thread, likely to enhance much the likelyhood of there being a Russian presence in OTL Mexico.